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Eusthenopteron
Eusthenopteron was a Devonian lobe-finned fish lived in 385 million years ago. Other Tetrapodomorphs includes Panderichthys (Lived in 380 million years ago) and Tiktaalik (Lived in 375 million years ago). Evolution Ichthyostega and Acanthostega were the first amphibians but however this fish is older than amphibians. Eusthenopteron-Panderichthys-Tiktaalik-Acanthostega-Ichthyostega-Living Reptiles, Amphibians, Birds and Mammals including the non-avian dinosaurs Panderichthys and Tiktaalik Panderichthys and Tiktaalik are Amphibian-like fishes (Tiktaalik has a nose like other Tetrapods). They appear in the Late Devonian Panderichthys appear in 380 million years ago and Tikaalik almost lived with the amphibians and lived over 385 million years ago. Tikaalik also could even go to muddy shallows and to the land (A little bit). The earliest amphibians Ichthyostega and Acanthostega are the first amphibians from the Latest Devonian first appear in Romer's Gap. The first amphibians came in 374 million years ago. Romer's Gap amphibians also include Mississippian amphibians like Crassigyrinus. Description Anatomically, Eusthenopteron shares many unique features in common with the earliest known tetrapods. Largest individuals grew up to 1.8 m (6.5 ft) in length. It shares a similar pattern of skull rooting bones with forms such as Ichthyostega and Acanthostega. Eusthenopteron, like other tetrapodomorph fishes, had internal nostrils, (or a choana) which are found only in land animals and sarcopterygians. It also had labyrinthodont teeth, characterized by infolded enamel, which characterizes all of the earliest known tetrapods as well. Like other fish-like sarcopterygians, Eusthenopteron possessed a two-part cranium, which hinged at mid-length along an intracranial joint. Eusthenopteron's notoriety comes from the pattern of its fin endoskeleton, which bears a distinct humerus, ulna, and radius (in the fore-fin) and femur, tibia, and fibula (in the pelvic fin). These appendicular long bones had epiphyseal growth plates that allowed substantial longitudinal growth through endochondral ossification, as in tetrapod long bones. These six appendicular bones also occur in tetrapods and are a synapomorphy of a large clade of sarcopterygians, possibly Tetrapodomorpha (the humerus and femur are present in all sarcoptergyians). Similarly, its elasmoid scales lack superficial odontodes composed of dentine and enamel; this loss appears to be a synapomorphy with more crownward tetrapodomorphs. In Late Devonian vertebrate speciation, descendants of pelagic lobe-finned fish – like Eusthenopteron – exhibited a sequence of adaptations: * Panderichthys, suited to muddy shallows; * Tiktaalik with limb-like fins that could take it onto land; * Early tetrapods in weed-filled swamps, such as: * Acanthostega which had feet with eight digits, * Ichthyostega with limbs. Descendants also included pelagic lobe-finned fish such as coelacanth species. Eusthenopteron differs significantly from some later Carboniferous tetrapods in the apparent absence of a recognized larval stage and a definitive metamorphosis. In even the smallest known specimen of Eusthenopteron foordi (at 29 mm), the lepidotrichia cover all of the fins, which does not happen until after metamorphosis in genera like Polyodon. This might indicate that Eusthenopteron developed directly, with the hatchling already attaining the general body form of the adult (Cote et al., 2002). So, Jarvik was perhaps not correct as he proposed (1980) Palaeospondylus gunni might have been the larva (tadpole-like) of Eusthenopteron. In The Land Before Time They appear in The Land Before Time VIII: The Big Freeze in the beginning when the Camptosaurus was swimming however this creature does not live with the dinosaurs (even reptiles and amphibians). Eusthenopteron had not appeared in other The Land Before Time movies. Trivia *This creature was the oldest (Not counting on Ammonite) in The Land Before Time (series). *This creature had not appear in The Land Before Time III: The Time of the Great Giving. *Coelanth and Eusthenopteron are the only Non-Tetrapod (Eusthenopteron look like a Tetrapod) Lobe-Finned Fish. *They maybe Swimming Sharptooths because of their jaws. *Lobe-Finned Fishes legs would be called Flippers. Category:Creatures before the dinosaurs Category:Other creatures Category:Swimmers Category:Land Before Time VIII: The Big Freeze characters Category:Characters who don't talk Category:One-Movie only characters Category:Sharptooth Category:Swimming Sharptooth Category:Land Before Time species